This program project consists of a collaborative study of the cellular and molecular aspects of the transport of respiratory gas between the ambient air and the sub-cellular sites of metabolism. The constituent research projects can be subdivided into: 1. Pulmonary cellular function involving lipid metabolism of the lung including Type II cells and the smooth muscle cells of the air ways. 2. Blood as a transport tissue including rapid chemical reactions of whole blood hemoglobin with respiratory gases and CO as well as the intracellular activity of carbonic anhydrase and speed of acid base readjustments in vivo. 3. Transport of respiratory gases in tissues including several unique techniques of estimating tissue PO2, such as mitochondrial oxygen consumption, 18O indicator dilution and CO-O2 myoglobin equilibrium, and the effect of pulsatility on capillary exchanges. Control of vascular smooth muscle by PO2 will be also investigated. There are three Core facilities: A) A mass spectrometer facility with two instruments for the measurement of stable isotopes, B) A spectrofluorometric analytical facility for measurement of intracellular metabolite concentrations and C) An administrative facility. This supplemental request has been submitted only five months after the initiation of the Program Project for two reasons; first, the Investigator responsible for the project on Cortisol-Dependent Alteration in Lung Type II Cells (IC) accepted a position elsewhere and Dr. J.F. Aronson, who was chosen in his stead, has prepared an updated version of the project which was originally approved and funded. Secondly, additional equipment is requested for the project on Fatty Acid Metabolism and Type II Alveolar Cells (IA) because it had been assumed at the time of the original application that a number of items of equipment in Dr. Aron Fisher's laboratory which belonged to the VA would continue to be available for this research. Unfortunately, the VA has required the immediate return of these instruments, a significant proportion of which are essential for the project.